Added WorldBorder support.

Core/src/main/java/com/songoda/core/world/WorldBorder.java

@@ -0,0 +1,89 @@
+package com.songoda.core.world;
+
+import com.songoda.core.compatibility.ServerVersion;
+import com.songoda.core.utils.NMSUtils;
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+public class WorldBorder {
+    
+    private static Class<?> packetPlayOutWorldBorderEnumClass;
+    private static Class<?> worldBorderClass;
+    private static Class<?> craftWorldClass;
+    private static Constructor<?> packetPlayOutWorldBorderConstructor;
+
+    static {
+        try {
+            Class<?> packetPlayOutWorldBorder = NMSUtils.getNMSClass("PacketPlayOutWorldBorder");
+
+            if(packetPlayOutWorldBorder != null) {
+                if (ServerVersion.isServerVersionAtLeast(ServerVersion.V1_11))
+                    packetPlayOutWorldBorderEnumClass = packetPlayOutWorldBorder.getDeclaredClasses()[0];
+                else
+                    packetPlayOutWorldBorderEnumClass = packetPlayOutWorldBorder.getDeclaredClasses()[1];
+                
+                worldBorderClass = NMSUtils.getNMSClass("WorldBorder");
+                craftWorldClass = NMSUtils.getCraftClass("CraftWorld");
+    
+                packetPlayOutWorldBorderConstructor = packetPlayOutWorldBorder.getConstructor(worldBorderClass,
+                        packetPlayOutWorldBorderEnumClass);
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static void send(Player player, Color color, double size, Location centerLocation) {
+        try {
+            if (centerLocation == null || centerLocation.getWorld() == null)
+                return;
+
+            Object worldBorder = worldBorderClass.getConstructor().newInstance();
+
+            if (ServerVersion.isServerVersionAtLeast(ServerVersion.V1_9)) {
+                Object craftWorld = craftWorldClass.cast(centerLocation.getWorld());
+                Method getHandleMethod = craftWorld.getClass().getMethod("getHandle");
+                Object worldServer = getHandleMethod.invoke(craftWorld);
+                NMSUtils.setField(worldBorder, "world", worldServer, false);
+            }
+
+            Method setCenter = worldBorder.getClass().getMethod("setCenter", double.class, double.class);
+            setCenter.invoke(worldBorder, centerLocation.getX(), centerLocation.getZ());
+
+            Method setSize = worldBorder.getClass().getMethod("setSize", double.class);
+            setSize.invoke(worldBorder, size);
+
+            Method setWarningTime = worldBorder.getClass().getMethod("setWarningTime", int.class);
+            setWarningTime.invoke(worldBorder, 0);
+            
+            Method setWarningDistance = worldBorder.getClass().getMethod("setWarningDistance", int.class);
+            setWarningDistance.invoke(worldBorder, 0);
+
+            Method transitionSizeBetween = worldBorder.getClass().getMethod("transitionSizeBetween", double.class,
+                    double.class, long.class);
+
+            if (color == Color.Green) {
+                transitionSizeBetween.invoke(worldBorder, size - 0.1D, size, 20000000L);
+            } else if (color == Color.Red) {
+                transitionSizeBetween.invoke(worldBorder, size, size - 1.0D, 20000000L);
+            }
+
+            @SuppressWarnings({"unchecked", "rawtypes"})
+            Object packet = packetPlayOutWorldBorderConstructor.newInstance(worldBorder,
+                    Enum.valueOf((Class<Enum>) packetPlayOutWorldBorderEnumClass, "INITIALIZE"));
+            NMSUtils.sendPacket(player, packet);
+        } catch (InstantiationException | InvocationTargetException | NoSuchMethodException | IllegalAccessException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public enum Color {
+
+        Blue, Green, Red
+
+    }
+}